Though you can cover even very long distances by car if you have the guts to, as soon as it comes to crossing water, you'll have to stick to a plane. The equation is the same as usual: limited space + long time of inactivity = whiny, annoying children.
The big difference towards a car is that when you're on a plane, you can't just stop and let your children run around a bit, and you even have to share it with a lot of other people (who probably want to have a rest). So how to keep the little ones calm?
Entertainment electronics cut in again. Modern airlines provide a small tv in the back of the seat even for economy class, or at least one hanging from the ceiling, which might be difficult for your kids to see if they're not sitting on the corridor side. If you don't have that kind of luxury, a camcorder with headphones will do the trick. Modern camcorders have a little flatscreen, so you can use it as a mobile tv/vcr combination. For older children, a laptop with a DVD-player can do the job as well. But keep in mind to charge the batteries before!
Airplane food is generally not very tasty. The free drinks, though, are acceptable, and if you're in with a baby or toddler, the cabin crew will surely help you warming up some milk. Still, you should bring some snacks in case your kid's don't like the food.
Even for adults, the pain in the ear from the pressurizing during liftoff and landing can be quite annoying, so how much more for children. If they're too young for chewing gum, a drink (best with a straw) also helps.
Be careful with your choice of toys. The playground size is very limited, and things easily get lost under the seat, or worse, under someone else's seat. You normally have a tray built in there, so you can set it as a limit. The temperature in airplanes tends to be slightly too cold, especially when your flight is ongoing for some time already and you haven't moved much. So it's useful to dress your kids in layers, that makes it easier to adjust. For yourself, avoid white clothes and have a spare shirt in your handluggage when you're dealing with babies.
Brigette Meier is an occassional author for http://www.e-nterests.com - visit the site for more interesting articles.